30 CFR 715.17 - Protection of the hydrologic system.
|Effluent characteristics||Maximum allowable 1||Average of daily values for 30 consecutive discharge days 1|
|1 Based on representative sampling.|
|2 In Arizona, Colorado, Montana, New Mexico, North Dakota, South Dakota, Utah, and Wyoming, total suspended solids limitations will be determined on a case-by-case basis, but they must not be greater than 45 mg/l (maximum allowable) and 30 mg/l (average of daily value for 30 consecutive discharge days) based on a representative sampling.|
|3 Where the application of neutralization and sedimentation treatment technology results in inability to comply with the manganese limitation set forth, the regulatory authority may allow the pH level in the discharge to exceed to a small extent the upper limit of 9.0 in order that the manganese limitations will be achieved.|
|4 Within the range 6.0 to 9.0.|
|Total suspended solids 2||70.0||35.0|
|pH 3||(4 )||(4 )|
The permittee shall plan and conduct coal mining and reclamation operations to minimize disturbance to the prevailing hydrologic balance in order to prevent long-term adverse changes in the hydrologic balance that could result from surface coal mining and reclamation operations, both on- and off-site. Changes in water quality and quantity, in the depth to ground water, and in the location of surface water drainage channels shall be minimized such that the postmining land use of the disturbed land is not adversely affected and applicable Federal and State statutes and regulations are not violated. The permittee shall conduct operations so as to minimize water pollution and shall, where necessary, use treatment methods to control water pollution. The permittee shall emphasize surface coal mining and reclamation practices that will prevent or minimize water pollution and changes in flows in preference to the use of water treatment facilities. Practices to control and minimize pollution include, but are not limited to, stabilizing disturbed areas through grading, diverting runoff, achieving quick growing stands of temporary vegetation, lining drainage channels with rock or vegetation, mulching, sealing acid-forming and toxic-forming materials, and selectively placing waste materials in backfill areas. If pollution can be controlled only by treatment, the permittee shall operate and maintain the necessary water-treatment facilities for as long as treatment is required.
(a) Water quality standards and effluent limitations. All surface drainage from the disturbed area, including disturbed areas that have been graded, seeded, or planted, shall be passed through a sedimentation pond or a series of sedimentation ponds before leaving the permit area. Sedimentation ponds shall be retained until drainage from the disturbed areas has met the water quality requirements of this section and the revegetation requirements of § 715.20 have been met. The regulatory authority may grant exemptions from this requirement only when the disturbed drainage area within the total disturbed area is small and if the permittee shows that sedimentation ponds are necessary to meet the effluent limitations of this paragraph and to maintain water quality in downstream receiving waters. For purpose of this section only, disturbed area shall not include those areas in which only diversion ditches, sedimentation ponds, or roads are installed in accordance with this section and the upstream area is not otherwise disturbed by the permittee. Sedimentation ponds required by this paragraph shall be constructed in accordance with paragraph (e) of this section in appropriate locations prior to any mining in the affected drainage area in order to control sedimentation or otherwise treat water in accordance with this paragraph. Discharges from areas disturbed by surface coal mining and reclamation operations must meet all applicable Federal and State laws and regulations and, at a minimum, the following numerical effluent limitations:
Effluent Limitations, in Milligrams Per Liter, mg/l, Except for pH
|Effluent characteristics||Maximum allowable 1||Average of daily values for 30 consecutive discharge days 1|
|Total suspended solids 2||70.0||35.0|
|pH 3||( 4 )||( 4 )|
1 Based on representative sampling.
2 In Arizona, Colorado, Montana, New Mexico, North Dakota, South Dakota, Utah, and Wyoming, total suspended solids limitations will be determined on a case-by-case basis, but they must not be greater than 45 mg/l (maximum allowable) and 30 mg/l (average of daily value for 30 consecutive discharge days) based on a representative sampling.
3 Where the application of neutralization and sedimentation treatment technology results in inability to comply with the manganese limitation set forth, the regulatory authority may allow the pH level in the discharge to exceed to a small extent the upper limit of 9.0 in order that the manganese limitations will be achieved.
4 Within the range 6.0 to 9.0.
(1) Any overflow or other discharge of surface water from the disturbed area within the permit area demonstrated by the permittee to result from a precipitation event larger than a 10-year, 24-hours frequency event will not be subject to the effluent limitations of paragraph (a).
(2) The permittee shall install, operate, and maintain adequate facilities to treat any water discharged from the disturbed area that violates applicable federal or State laws or regulations or the limitations of paragraph (a). If the pH of waters to be discharged from the disturbed area is normally less than 6.0, an automatic line feeder or other neutralization process approved by the regulatory authority shall be installed operated, and maintained. If, the regulatory authority finds (i) that small and infrequent treatment requirements to meet applicable standards do not necessitate use of an automatic neutralization process, and (ii) that the mine normally produces less than 500 tons of coal per day, then the regulatory authority may approve the use of a manual system if the permittee ensures consistent and timely treatment.
(3) The effluent limitations for manganese shall be applicable only to acid drainage.
(b) Surface-water monitoring.
(i) Provides adequate monitoring of all discharge from the disturbed area.
(ii) Provides adequate data to describe the likely daily and seasonal variation in discharges from the disturbed area in terms of water flow, pH, total iron, total managanese, and total suspended solids and, if requested by the regulatory authority, any other parameter characteristic of the discharge.
(iii) Provides monitoring at appropriate frequencies to measure normal and abnormal variations in concentrations.
(v) Within sixty (60) days of the end of each sixty (60) day sample collection period, a report of all samples shall be made to the regulatory authority, unless the discharge for which water monitoring reports are required is subject to regulation by a National Pollution Discharge Elimination System (NPDES) permit issued in compliance with the Clean Water Act of 1977 (33 U.S.C. 1251-1378), (A) which includes equivalent reporting requirements, and (B) which requires filing of the water monitoring report within 90 days or less of sample collection. For such discharges, the reporting requirements of this paragraph may be satisfied by submitting to the regulatory authority on the same time schedule as required by the NPDES permit or within ninety (90) days following sample collection, whichever is earlier, either (1) a copy of the completed reporting form filed to meet the NPDES permit requirements, or (2) a letter identifying the State or Federal government official with whom the reporting form was filed to meet the NPDES permit requirements and the date of filing. In all cases in which analytical results of the sample collections indicate a violation of a permit condition or applicable standard has occurred, the operator shall notify the regulatory authority immediately. Where an NPDES permit effluent limitation requirement has been violated, the permittee should forward a copy of the Discharge Monitoring Report, EPA Form 3320-1, concurrently with notification of the violation.
(2) After disturbed areas have been regraded and stabilized in accordance with this part, the permittee shall monitor surface water flow and quality. Data from this monitoring shall be used to demonstrate that the quality and quantity of runoff without treatment will be consistent with the requirement of this section to minimize disturbance to the prevailing hydrologic balance and with the requirements of this part to attain the approved postmining land use. These data shall provide a basis for approval by the regulatory authority for removal of water quality or flow control systems and for determining when the requirements of this section are met. The regulatory authority shall determine the nature of data, frequency of collection, and reporting requirements.
(3) Equipment, structures, and other measures necessary to accurately measure and sample the quality and quantity of surface water discharges from the disturbed area of the permit area shall be properly installed, maintained, and operated and shall be removed when no longer required.
(c) Diversion and conveyance of overland flow away from disturbed areas. In order to minimize erosion and to prevent or remove water from contacting toxic-producing deposits, overland flow from undisturbed areas may, if required or approved by the regulatory authority, be diverted away from disturbed areas by means of temporary or permanent diversion structures. The following requirements shall be met:
(1) Temporary diversion structures shall be constructed to safely pass the peak runoff from a precipitation event with a one year recurrence interval, or a larger event as specified by the regulatory authority. The design criteria must assure adequate protection of the environment and public during the existence of the temporary diversion structure.
(2) Permanent diversion structures are those remaining after mining and reclamation and approved for retention by the regulatory authority and other appropriate State and Federal agencies. To protect fills and property and to avoid danger to public health and safety, permanent diversion structures shall be constructed to safely pass the peak runoff from a precipitation event with a 100-year recurrence interval, or a larger event as specified by the regulatory authority. Permanent diversion structures shall be constructed with gently sloping banks that are stabilized by vegetation. Asphalt, concrete, or other similar linings shall not be used unless specifically required to prevent seepage or to provide stability and are approved by the regulatory authority.
(3) Diversions shall be designed, constructed, and maintained in a manner to prevent additional contributions of suspended solids to streamflow or to runoff outside the permit area to the extent possible, using the best technology currently available. In no event shall such contributions be in excess of requirements set by applicable State or Federal law. Appropriate sediment control measures for these diversions shall include, but not be limited to, maintenances of appropriate gradients, channel lining, revegetation, roughness structures, and detention basins.
(d) Stream channel diversions.
(1) Flow from perennial and intermittent streams within the permit area may be diverted only when the diversions are approved by the regulatory authority and they are in compliance with local, State, and Federal statutes and regulations. When streamflow is allowed to be diverted, the new stream channel shall be designed and constructed to meet the following requirements:
(i) The average stream gradient shall be maintained and the channel designed, constructed, and maintained to remain stable and to prevent additional contributions of suspended solids to streamflow, or to runoff outside the permit area to the extent possible, using the best technology currently available. In no event shall such contributions be in excess of requirements set by applicable State or Federal law. Erosion control structures such as channel lining structures, retention basins, and artificial channel roughness structures shall be used only when approved by the regulatory agency for temporary diversions where necessary or for permanent diversions where they are stable and will require only infrequent maintenance.
(ii) Channel, bank, and flood-plain configurations shall be adequate to safely pass the peak runoff of a precipitation event with a 10-year recurrence interval for temporary diversions and a 100-year recurrence interval for permanent diversions, or larger events as specified by the regulatory authority.
(iii) Fish and wildlife habitat and water and vegetation of significant value for wildlife shall be protected in consultation with appropriate State and Federal fish and wildlife management agencies.
(2) All temporary diversion structures shall be removed and the affected land regraded and revegetated consistent with the requirements of §§ 715.14 and 715.20. At the time such diversions are removed, the permittee shall ensure that downstream water treatment facilities previously protected by the diversion are modified or removed to prevent overtopping or failure of the facilities.
(3) Buffer zone. No land within 100 feet of an intermittent or perennial stream shall be disturbed by surface coal mining and reclamation operations unless the regulatory authority specifically authorizes surface coal mining and reclamation operations through such a stream. The area not to be disturbed shall be designated a buffer zone and marked as specified in § 715.12.
(e) Sedimentation ponds -
(1) General requirements. Sedimentation ponds shall be used individually or in series and shall -
(i) Be constructed before any disturbance of the undisturbed area to be drained into the pond;
(iii) Meet all the criteria of this section.
(2) Sediment storage volume. Sedimentation ponds shall provide a minimum sediment storage volume.
(3) Detention time. Sedimentation ponds shall provide the required theoretical detention time for the water inflow or runoff entering the pond from a 10-year, 24-hour precipitation event (design event).
(4) Dewatering. The water storage resulting from inflow shall be removed by a nonclogging dewatering device or a conduit spillway approved by the regulatory authority. The dewatering device shall not be located at a lower elevation than the maximum elevation of the sedimentation storage volume.
(6) The design, construction, and maintenance of a sedimentation pond or other sediment control measures in accordance with this section shall not relieve the person from compliance with applicable effluent limitations as contained in paragraph (a) of this section.
(8) Sediment shall be removed from sedimentation ponds.
(9) An appropriate combination of principal and emergency spillways shall be provided to safely discharge the runoff from a 25-year, 24-hour precipitation event, or larger event specified by the regulatory authority. The elevation of the crest of the emergency spillway shall be a minimum of 1.0 foot above the crest of the principal spillway. Emergency spillway grades and allowable velocities shall be approved by the regulatory authority.
(10) The minimum elevation at the top of the settled embankment shall be 1.0 foot above the water surface in the pond with the emergency spillway flowing at design depth. For embankments subject to settlement, this 1.0 foot minimum elevation requirement shall apply at all times, including the period after settlement.
(11) The constructed height of the dam shall be increased a minimum of 5 percent over the design height to allow for settlement, unless it has been demonstrated to the regulatory authority that the material used and the design will ensure against all settlement.
(13) The combined upstream and downstream side slopes of the settled embankment shall not be less than 1v:5h, with neither slope steeper than 1v:2h. Slopes shall be designed to be stable in all cases, even if flatter side slopes are required.
(14) The embankment foundation areas shall be cleared of all organic matter, all surfaces sloped to no steeper than 1v:1h, and the entire foundation surface scarified.
(15) The fill material shall be free of sod, large roots, other large vegetative matter, and frozen soil, and in on case shall coal-processing waste be used.
(16) The placing and spreading of fill material shall be started at the lowest point of the foundation. The fill shall be brought up in horizontal layers of such thickness as is required to facilitate compaction and meet the design requirements of this section. Compaction shall be conducted as specified in the design approved by the regulatory authority.
(17) If a sedimentation pond has an embankment that is more than 20 feet in height, as measured from the upstream toe of the embankment to the crest of the emergency spillway, or has a storage volume of 20 acre-feet or more, the following additional requirements shall be met:
(i) An appropriate combination of principal and emergency spillways shall be provided to discharge safely the runoff resulting from a 100-year, 24-hour precipitation event, or a larger event specified by the regulatory authority.
(iv) The criteria of the Mine Safety and Health Administration as published in 30 CFR 77.216 shall be met.
(18) Each pond shall be designed and inspected during construction under the supervision of, and certified after construction by, a registered professional engineer.
(19) The entire embankment including the surrounding areas disturbed by construction shall be stabilized with respect to erosion by a vegetative cover or other means immediately after the embankment is completed. The active upstream face of the embankment where water will be impounded may be riprapped or otherwise stabilized. Areas in which the vegetation is not successful or where rills and gullies develop shall be repaired and revegetated in accordance with § 715.20.
(20) All ponds, including those not meeting the size or other criteria of 30 CFR 77.216(a), shall be examined for structural weakness, erosion, and other hazardous conditions, and reports and modifications shall be made to the regulatory authority, in accordance with 30 CFR 77.216-3. With the approval of the regulatory authority, dams not meeting these criteria (30 CFR 77.216(a)) shall be examined four times per year.
(21) Sedimentation ponds shall not be removed until the disturbed area has been restored, and the vegetation requirements of § 715.20 are met and the drainage entering the pond has met the applicable State and Federal water quality requirements for the receiving stream. When the sedimentation pond is removed, the affected land shall be regraded and revegetated in accordance with §§ 715.14, 715.16, and 715.20, unless the pond has been approved by the regulatory authority for retention as being compatible with the approved postmining land use. If the regulatory authority approves retention, the sedimentation pond shall meet all the requirements for permanent impoundments of paragraph (k) of this section.
(i) Where surface mining activities are proposed to be conducted on steep slopes, as defined in § 716.2 of this chapter, special sediment control measures may be followed if the person has demonstrated to the regulatory authority that a sedimentation pond (or series of ponds) constructed according to paragraph (e) of this section -
(A) Will jeopardize public health and safety; or
(B) Will result in contributions of suspended solids to streamflow in excess of the incremental sediment volume trapped by the additional pond size required.
(ii) Special sediment control measures shall include but not be limited to -
(A) Designing, constructing, and maintaining a sedimentation pond as near as physically possible to the disturbed area which complies with the design criteria of this section to the maximum extent possible.
(B) A plan and commitment to employ sufficient onsite sedimentation control measures including bench sediment storage, filtration by natural vegetation, mulching, and prompt revegetation which, in conjunction with the required sediment pond, will achieve and maintain applicable effluent limitations. The plan submitted pursuant to this paragraph shall include a detailed description of all onsite control measures to be employed, a quantitative analysis demonstrating that onsite sedimentation control measures, in conjunction with the required sedimentation pond, will achieve and maintain applicable effluent limitations, and maps depicting the location of all onsite sedimentation control measures.
(f) Discharge structures. Discharges from sedimentation ponds and diversions shall be controlled, where necessary, using energy dissipators, surge ponds, and other devices to reduce erosion and prevent deepening or enlargement of stream channels and to minimize disturbances to the hydrologic balance.
(g) Acid and toxic materials. Drainage from acid-forming and toxic-forming mine waste materials and soils into ground and surface water shall be avoided by -
(1) Identifying, burying, and treating where necessary, spoil or other materials that, in the judgment of the regulatory authority, will be toxic to vegetation or that will adversely affect water quality if not treated or buried. Such material shall be disposed of in accordance with the provision of § 715.14(j);
(2) Preventing or removing water from contact with toxic-producing deposits;
(3) Burying or otherwise treating all toxic or harmful materials within 30 days, if such materials are subject to wind and water erosion, or within a lesser period designated by the regulatory authority. If storage of such materials is approved, the materials shall be placed on impermeable material and protected from erosion and contact with surface water. Coal waste ponds and other coal waste materials shall be maintained according to paragraph (g)(4) of this section, and § 715.18 shall apply;
(4) Burying or otherwise treating waste materials from coal preparation plants no later than 90 days after the cessation of the filling of the disposal area. Burial or treatment shall be in accordance with § 715.14(j);
(5) Casing, sealing or otherwise managing boreholes, shafts, wells, and auger holes or other more or less horizontal holes to prevent pollution of surface or ground water and to prevent mixing of ground waters of significantly different quality. All boreholes that are within the permit area but are outside the surface coal mining area or which extend beneath the coal to be mined and into water bearing strata shall be plugged permanently in a manner approved by the regulatory authority, unless the boreholes have been approved for use in monitoring;
(6) Taking such other actions as required by the regulatory authority.
(h) Ground water -
(1) Recharge capacity of reclaimed lands. The disturbed area shall be reclaimed to restore approximate premining recharge capacity through restoration of the capability of the reclaimed areas as a whole to transmit water to the ground water system. The recharge capacity should be restored to support the approved postmining land use and to minimize disturbances to the prevailing hydrologic balance at the mined area and in associated offsite areas. The permittee shall be responsible for monitoring according to paragraph (h)(3) of this section to ensure operations conform to this requirement.
(2) Ground water systems. Backfilled materials shall be placed to minimize adverse effects on ground water flow and quality, to minimize offsite effects, and to support the approved postmining land use. The permittee shall be responsible for performing monitoring according to paragraph (h)(3) of this section to ensure operations conform to this requirement.
(3) Monitoring. Ground water levels, infiltration rates, subsurface flow and storage characteristics, and the quality of ground water shall be monitored in a manner approved by the regulatory authority to determine the effects of surface coal mining and reclamation operations on the recharge capacity of reclaimed lands and on the quantity and quality of water in ground water systems at the mine area and in associated offsite areas. When operations are conducted in such a manner that may affect the ground water system, ground water levels and ground water quality shall be periodically monitored using wells that can adequately reflect changes in ground water quantity and quality resulting from such operations. Sufficient water wells must be used by the permittee. The regulatory authority may require drilling and development of additional wells if needed to adequately monitor the ground water system. As specified and approved by the regulatory authority, additional hydrologic tests, such as infiltration tests and aquifer tests, must be undertaken by the permittee to demonstrate compliance with paragraph (h) (1) and (2) of this section.
(i) Water rights and replacement. The permittee shall replace the water supply of an owner of interest in real property who obtains all or part of his supply of water for domestic, agricultural, industrial, or other legitimate use from an underground or surface source where such supply has been affected by contamination, diminution, or interruption proximately resulting from surface coal mine operation by the permittee.
(j) Alluvial valley floors west of the 100th meridian west longitude.
(1) Surface coal mining operations conducted in or adjacent to alluvial valley floors shall be planned and conducted so as to preserve the essential hydrologic functions of these alluvial valley floors throughout the mining and reclamation process. These functions shall be preserved by maintaining or reestablishing those hydrologic and biologic characteristics of the alluvial valley floor that are necessary to support the functions. The permittee shall provide information to the regulatory authority as required in paragraph (j)(3) of this section to allow identification of essential hydrologic functions and demonstrate that the functions will be preserved. The characteristics of an alluvial valley floor to be considered include, but are not limited to -
(i) The longitudinal profile (gradient), cross-sectional shape, and other channel characteristics of streams that have formed within the alluvial valley floor and that provide for maintenance of the prevailing conditions of surface flow;
(ii) Aquifers (including capillary zones and perched water zones) and confining beds within the mined area which provide for storage, transmission, and regulation of natural ground water and surface water that supply the alluvial valley floors;
(v) Configuration and stability of the land surface in the flood plain and adjacent low terraces in alluvial valley floors as they allow or facilitate irrigation with flood waters or subirrigation and maintain erosional equilibrium; and
(vi) Moisture-holding capacity of soils (or plant growth medium) within the alluvial valley floors, and physical and chemical characteristics of the subsoil which provide for sustained vegetation growth or cover through dry months.
(2) Surface coal mining operations located west of the 100th meridian west longitude shall not interrupt, discontinue, or preclude farming on alluvial valley floors and shall not materially damage the quantity or quality of surface or ground water that supplies these valley floors unless the premining land use has been undeveloped rangeland which is not significant to farming on the alluvial valley floors or unless the area of affected alluvial valley floor is small and provides negligible support for the production from one or more farms. This paragraph (j)(2) does not apply to those surface coal mining operations that -
(i) Were in production in the year preceding August 3, 1977, were located in or adjacent to an alluvial valley floor, and produced coal in commercial quantities during the year preceding August 3, 1977; or
(i) Before surface mining and reclamation operations authorized under paragraph (j)(2) of this section may be issued a new revised or amended permit, the permittee shall submit, for regulatory authority approval, detailed surveys and baseline data to establish standards against which the requirements of paragraph (j)(1) of this section may be measured and from which the degree of material damage to the quantity and quality of surface and ground water that supply the alluvial valley floors may be assessed. The surveys and date shall include -
(A) A map at a scale determined by the regulatory authority, showing the location and configuration of the alluvial valley floor;
(B) Baseline data covering a full water year for each of the hydrologic functions identified in paragraph (j)(1) of this section;
(C) Plans showing how the operation will avoid, during mining and reclamation, interruption, discontinuance, or preclusion of farming on the alluvial valley floors and will not materially damage the quantity or quality of water in surface and ground water systems that supply such valley floors;
(E) Such other data as the regulatory authority may require.
(4) The holder of a Federal coal lease or the fee holder of any coal deposit located within or adjacent to an alluvial valley floor west of the 100th meridian west from which coal was not produced in commercial quantities between August 3, 1976, and August 3, 1977, and for which no specific permit by the appropriate State or Federal regulatory authority to conduct surface coal mining operations in the alluvial valley floors has been obtained, may be entitled to an exchange of the Federal coal lease for a lease of other Federal coal deposits under section 510(b)(5) of the Act, or to the conveyance by the Secretary of fee title to other available Federal coal deposits in exchange for the fee title to such deposits under section 206 of the Federal Land Policy and Management Act of 1976 (90 Stat. 2743), if the Secretary determines that substantial financial and legal commitments were made by the operator prior to January 1, 1977, in connection with surface coal mining operations on such lands.
(k) Permanent impoundments. The permittee may construct, if authorized by the regulatory agency pursuant to this paragraph and § 715.13, permanent water impoundments on mining sites as a part of reclamation activities only when they are adequately demonstrated to be incompliance with §§ 715.13 and 715.14 in addition to the following requirements:
(1) The size of the impoundment is adequate for its intended purposes.
(2) The impoundment dam construction is designed to achieve necessary stability with an adequate margin of safety compatible with that of structures constructed under Pub. L. 83-566 (16 U.S.C. 1006).
(3) The quality of the impounded water will be suitable on a permanent basis for its intended use and discharges from the impoundment will not degrade the quality of receiving waters below the water quality standards established pursuant to applicable Federal and State law.
(4) The level of water will be reasonably stable.
(5) Final grading will comply with the provisions of § 715.14 and will provide adequate safety and access for proposed water users.
(6) Water impoundments will not result in the diminution of the quality or quantity of water used by adjacent or surrounding landowners for agricultural, industrial, recreational, or domestic uses.
(l) Hydrologic impact of roads -
(1) General. Access and haul roads and associated bridges, culverts, ditches, and road rights-of-way shall be constructed, maintained, and reclaimed to prevent additional contributions of suspended solids to streamflow, or to runoff outside the permit area to the extent possible, using the best technology currently available. In no event shall the contributions be in excess of requirements set by applicable State or Federal law. All access and haul roads shall be removed and the land affected regraded and revegetated consistent with the requirements of §§ 715.14 and 715.20, unless retention of a road is approved as part of a postmining land use under § 715.13 as being nessary to support the postmining land use or necessary to adequately control erosion and the necessary maintenance is assured.
(i) All roads, insofar as possible, shall be located on ridges or on the available flatter and more stable slopes to minimize erosion. Stream fords are prohibited unless they are specifically approved by the regulatory authority as temporary routes across dry streams that will not adversely affect sedimentation and that will not be used for coal haulage. Other stream crossings shall be made using bridges, culverts or other structures designed and constructed to meet the requirements of this paragraph. Roads shall not be located in active stream channels nor shall they be constructed or maintained in a manner that increases erosion or causes significant sedimentation or flooding. However, nothing in this paragraph will be construed to prohibit relocation of stream channels in accordance with paragraph (d) of this section.
(ii) In order to minimize erosion and subsequent disturbances of the hydrologic balance, roads shall be constructed in compliance with the following grade restrictions or other grades determined by the regulatory authority to be necessary to control erosion:
(A) The overall sustained grade shall not exceed 1v:10h (10 percent).
(B) The maximum grade greater than 10 percent shall not exceed 1v:6.5h (15 percent) for more than 300 feet.
(C) There shall not be more than 300 feet of grade exceeding 10 percent within each 1,000 feet.
(iii) All access and haul roads shall be adequately drained using structures such as, but not limited to, ditches, water barriers, cross drains, and ditch relief drains. For access and haul roads that are to be maintained for more than 1 year, water-control structures shall be designed with a discharge capacity capable of passing the peak runoff from a 10-year, 24-hour precipitation event. Drainage pipes and culverts shall be constructed to avoid plugging or collapse and erosion at inlets and outlets. Drainage ditches shall be provided at the toe of all cut slopes formed by construction of roads. Trash racks and debris basins shall be installed in the drainage ditches wherever debris from the drainage area could impair the functions of drainage and sediment control structures. Ditch relief and cross drains shall be spaced according to grade. Effluent limitations of paragraph (a) of this section shall not apply to drainage from access and hauls roads located outside the disturbed area as defined in this section unless otherwise specified by the regulatory authority.
(iv) Access and haul roads shall be surfaced with durable material. Toxic- or acid-forming substances shall not be used. Vegetation may be cleared only for the essential width necessary for road and associated ditch construction and to serve traffic needs.
(i) Access and haul roads shall be routinely maintained by means such as, but not limited to, wetting, scraping or surfacing.
(ii) Ditches, culverts, drains, trash racks, debris basins and other structures serving to drain access and haul roads shall not be restricted or blocked in any manner that impedes drainage or adversely affects the intended purpose of the structure.
(m) Hydrologic impacts of other transport facilities. Railroad loops, spurs, sidings and other transport facilities shall be constructed, maintained and reclaimed to control diminution or degradation of water quality and quantity and to prevent additional contributions of suspended solids to streamflow, or to run-off outside the permit area to the extent possible, using the best technology currently available. In no event shall contributions be in excess of requirements set by applicable State or Federal law.
(n) Discharge of waters into underground mines. Surface and ground waters shall not be discharged or diverted into underground mine workings.